Updates on surgical treatments for pediatric scoliosis

Accuracy and postoperative assessment of robot-assisted placement of pedicle screws during scoliosis surgery compared with conventional freehand technique: a systematic review and meta-analysis

STUDY DESIGN

A systematic review and meta-analysis.

BACKGROUND

The complexity of human anatomical structures and the variability of vertebral body structures in patients with scoliosis pose challenges in pedicle screw placement during spinal deformity correction surgery. Through technological advancements, robots have been introduced in spinal surgery to assist with pedicle screw placement.

METHODS

A systematic search was conducted using PubMed, Cochrane, Embase, and CNKI databases and comparative studies assessing the accuracy and postoperative efficacy of pedicle screw placement using robotic assistance or freehand techniques in patients with scoliosis were included. The analysis evaluated the accuracy of screw placement, operative duration, intraoperative blood loss, length of postoperative hospital stay, and complications.

RESULTS

Seven studies comprising 584 patients were included in the meta-analysis, with 282 patients (48.3%) in the robot-assisted group and 320 (51.7%) in the freehand group. Robot-assisted placement showed significantly better clinically acceptable screw placement results compared with freehand placement (odds ratio [OR]: 2.61, 95% confidence interval [CI]: 1.75-3.91, P < 0.0001). However, there were no statistically significant differences in achieving "perfect" screw placement between the two groups (OR: 1.52, 95% CI: 0.95-2.46, P = 0.08). The robot-assisted group had longer operation durations (mean deviation [MD]: 43.64, 95% CI: 22.25-64.74, P < 0.0001) but shorter postoperative hospital stays (MD: - 1.12, 95% CI: - 2.15 to - 0.08, P = 0.03) than the freehand group. There were no significant differences in overall complication rates or intraoperative blood loss between the two groups. There was no significant difference in Cobb Angle between the two groups before and after operation.

CONCLUSION

Robot-assisted pedicle screw placement offers higher accuracy and shorter hospital stay than freehand placement in scoliosis surgery; although the robotics approach is associated with longer operative durations, similar complication rates and intraoperative blood loss.

Paraspinous Muscle Flaps in Complex Pediatric Spine Surgeries: A 12-Year Single Institution Experience

PURPOSE

The benefits of paraspinous flaps in adult complex spine surgery patients are established in the literature; however, their use in pediatric patients has not been well described. This study compares clinical outcomes with and without paraspinous muscle flap closure in pediatric patients who have undergone spine surgery.

METHODS

We conducted a retrospective review of all pediatric spine surgeries at the University of California, San Francisco from 2011 to 2022. Patients were divided into 2 cohorts based on whether the plastic surgery service closed or did not close the wound with paraspinous muscle flaps. We matched patients by age, American Society of Anesthesiology classification, prior spinal surgical history, and diagnosis. Surgical outcomes were compared between the 2 cohorts.

RESULTS

We identified 226 pediatric patients who underwent at least one spinal surgery, 14 of whom received paraspinous flap closure by plastic surgery. They were matched in a 1:4 ratio with controls (n = 56) that did not have plastic surgery closure. The most common indication for plastic surgery involvement was perceived complexity of disease by the spine surgeon with concern for inadequate healthy tissue coverage (78.6%), followed by infection (21.4%). Postoperative complications were similar between the two groups. The plastic surgery cohort had a higher rate of patients who were underweight (57.1% vs 14.3%, P < 0.01) and had positive preoperative wound cultures (28.6% vs 8.9%, P = 0.05), as well as a higher rate of postoperative antibiotic usage (78.6 vs 17.9%, P < 0.01). There was no difference in recorded postoperative outcomes.

CONCLUSIONS

Spine surgeons requested paraspinous flap closure for patients with more complex disease, preoperative infections, history of chemotherapy, or if they were underweight. Patients with paraspinous flap coverage did not have increased postoperative complications despite their elevated risk profile. Our findings suggest that paraspinous muscle flaps should be considered in high-risk pediatric patients who undergo spine surgery.

Comparison of the Accuracy of Pedicle Screw Placement Using a Fluoroscopy-Assisted Free-Hand Technique with Robotic-Assisted Navigation Using an O-Arm or 3D C-Arm in Scoliosis Surgery

STUDY DESIGN

Retrospective.

OBJECTIVES

To report and compare the application of robotic-assisted navigation with an O-arm or three-dimensional (3D) C-arm-assisted pedicle screw insertion in scoliosis surgery, and compare with free-hand technique.

METHODS

One hundred and forty-four scoliosis patients were included in this study. Ninety-two patients underwent robotic-assisted pedicle screw insertion (Group A), and 52 patients underwent freehand fluoroscopy-guided pedicle screw insertion (Group B). Group A was further divided into Subgroup AI (n = 48; robotic-assisted navigation with an O-arm) and Subgroup AII (n = 44; robotic-assisted navigation with a 3D C-arm). The evaluated clinical outcomes were operation time, blood loss, radiation exposure, postoperative hospital stay, and postoperative complications. The clinical outcomes, coronal and sagittal scoliosis parameters and the accuracy of the pedicle screw placement were assessed.

RESULTS

There were no significant differences in blood loss and postoperative hospital stay between Groups A and B (P = .406, P = .138, respectively). Radiation exposure for patients in Group A (Subgroups AI or AII) was higher than that in Group B (P < .005), and Subgroup AI had higher patient radiation exposure compared with Subgroup AII (P < .005). The operation time in Subgroup AII was significantly longer than that in Subgroup AI and Group B (P = .016, P = .032, respectively). The proportion of clinically acceptable screws was higher in Group A (Subgroups AI or AII) compared with Group B (P < .005).

CONCLUSIONS

Robotic-assisted navigation with an O-arm or 3D C-arm effectively increased the accuracy and safety in scoliosis surgery. Compared with robotic-assisted navigation with a 3D C-arm, robotic-assisted navigation with an O-arm was more efficient intraoperatively.

Growing Rod versus Posterior Spinal Fusion Treatment of Juvenile Idiopathic Scoliosis: Unique Characteristics and Surgical Outcomes

Progressive spinal curvature in juvenile idiopathic scoliosis (JIS) is challenging to treat. When conservative management fails, treatments include growing rods (GRs) or posterior spinal fusion (PSF). The purpose of this study is to compare the patient characteristics and outcomes of GR and PSF treatment of JIS. We performed a retrospective review of demographic, radiographic, and surgical data for all JIS patients requiring surgical treatment between 2012 and 2020. Patients who underwent any GR treatment were compared to PSF patients. A total of 36 patients (13 GR, 23 PSF) were reviewed. PSF patients had a larger pre-operative spinal height (p = 0.002), but similar pre-operative major curve magnitudes (p = 0.558). PSF treatment resulted in similar change in the T1-S1 length (p = 0.002), but a greater correction of the curve magnitude (p < 0.055) compared to GR patients. Eight patients initially treated with GRs later underwent definitive PSF treatment. This subset of patients had a greater spinal height before PSF (p = 0.006), but similar immediate post-PSF T1-S1 lengths (p = 0.437) and smaller changes in spinal height from PSF (p = 0.020) than primary PSF patients. At final follow-up, patients who underwent primary PSF versus PSF after GR had similar spinal heights (p = 0.842). The surgical intervention chosen to manage progressive JIS often differs based on patient characteristics. While this choice may impact immediate outcomes, the outcomes at final follow up are similar.

Impact of pleural effusion at an early period after posterior spinal fusion for adolescent idiopathic scoliosis on future pulmonary function and lung volume

Background

Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) has a potential risk for postoperative pleural effusion. Although pleural effusion at an early period after PSF for AIS occurs with a relatively high frequency and occasionally requires some treatments, the impact of postoperative pleural effusion on future pulmonary function or lung volume (LV) has not been clarified to date. The aim of this study was to evaluate the effect of pleural effusion after PSF for AIS on the postoperative pulmonary function and LV.

Methods

A total of 114 consecutive patients who underwent PSF for AIS followed up greater than 2 years at our institute were retrospectively reviewed. We evaluated postoperative pleural effusion by computed tomography (CT) at the 1-week follow-up and divided patients into the pleural effusion (PF) and non-pleural effusion (NP) groups. We investigated spirometry parameters recorded for testing included vital capacity (VC), forced expiratory volume in the first second (FEV1), %VC, and FEV1% and measured the LV using CT images and a workstation at baseline and 2 years after surgery.

Results

A total of 87 (76.3%) patients with postoperative pleural effusion were identified, but all patients were asymptomatic and did not require additional treatment for postoperative pleural effusion. All pulmonary function parameters at the 2-year follow-up exhibited no significant differences between the two groups. Although preoperative left LV (1.21±0.30 L vs. 1.36±0.34 L; p=.022) and total LV (2.68±0.62 L vs. 2.99±0.73 L; p=.031) were significantly lower in the PF group than in the NP group, all postoperative LV parameters were similar between the two groups.

Conclusions

Pleural effusion at an early period after PSF for AIS was a postoperative occurrence without an impact on future pulmonary function and LV.

Safety and accuracy of cannulated pedicle screw placement in scoliosis surgery: a comparison of robotic-navigation, O-arm-based navigation, and freehand techniques

PURPOSE

To compare the safety and accuracy of cannulated pedicle screw placement using a robotic-navigation technique, O-arm-based navigation technique, or freehand technique.

METHODS

This study analyzed 106 consecutive patients who underwent scoliosis surgery. Thirty-two patients underwent robotic-navigation-assisted pedicle screw insertion (Group 1), 34 patients underwent O-arm-based navigation-guided pedicle screw insertion (Group 2), and 40 patients underwent freehand pedicle screw insertion (Group 3). The primary outcome measure was the accuracy of screw placement. Secondary outcome parameters included operation time, blood loss, radiation exposure, and postoperative stay.

RESULTS

A total of 2035 cannulated pedicle screws were implanted in 106 patients. The accuracy rate of the first pedicle screw placement during operation was significantly greater in Group 1 (94.7%) than in Group 2 (89.2%; P < 0.001). The accuracy rate of pedicle screw placement postoperatively decreased in the order of Group 1 (96.7%) > Group 2 (93.0%) > Group 3 (80.4%; P < 0.01). There were no significant differences in blood loss or postoperative stay among the three groups (P > 0.05). The operation times of Group 1 and Group 2 were significantly longer than that of Group 3 (P < 0.05).

CONCLUSION

The robotic-navigation and O-arm-based navigation techniques effectively increased the accuracy and safety of pedicle screw insertion alternative to the freehand technique in scoliosis surgery. Compared with the O-arm-based navigation technique, the robotic-navigation technique increases the mean operation time, but also increases the accuracy of pedicle screw placement. A three-dimensional scan after insertion of the K-wire may increase the accuracy of pedicle screw placement in the O-arm-based navigation technique.

YouTube as a source of information on pediatric scoliosis: a reliability and educational quality analysis

PURPOSE

To assess the reliability and educational quality of YouTube videos related to pediatric scoliosis.

METHODS

In December 2020, searches of "pediatric scoliosis", "idiopathic scoliosis", "scoliosis in children", and "curved spine in children" were conducted using YouTube. The first 50 results of each search were analyzed according to upload source and content. The Journal of the American Medical Association (JAMA) Benchmark Criteria were used to assess reliability (score 0-4), and educational quality was evaluated using the Global Quality Score (GQS; score 0-5) and Pediatric Scoliosis-Specific Score (PSS; score 0-15). Differences in scores based on upload source and content were determined by Analysis of Variance (ANOVA) or Kruskal-Wallis tests. Multivariate linear regressions identified any independent predictors of reliability and educational quality.

RESULTS

After eliminating duplicates, 153 videos were analyzed. Videos were viewed 28.5 million times in total, averaging 186,160.3 ± 1,012,485.0 views per video. Physicians (54.2%) and medical sources (19.0%) were the most common upload sources, and content was primarily categorized as disease-specific (50.0%) and patient experience (25.5%). Videos uploaded by patients achieved significantly lower JAMA scores (p = 0.004). Conversely, academic or physician-uploaded videos scored higher on PSS (p = 0.003) and demonstrated a trend towards improved GQS (p = 0.051). Multivariate analysis determined longer video duration predicted higher scores on all measures. However, there were no independent associations between upload source or content and assessment scores.

CONCLUSION

YouTube contains a large repository of videos concerning pediatric scoliosis; however, the reliability and educational quality of these videos were low.

LEVEL OF EVIDENCE

V.

Prediction of post-operative adding-on or compensatory lumbar curve correction after anterior vertebral body tethering

PURPOSE

Anterior Vertebral Body Tethering (AVBT), a fusionless surgical technique based on growth modulation, aims to correct pediatric scoliosis over time. However, medium-term curvature changes of the non-instrumented distal lumbar curve remains difficult to predict. The objective was to biomechanically analyze the level below the LIV to evaluate whether adding-on or compensatory lumbar curve after AVBT can be predicted by intervertebral disc (ID) wedging and force asymmetry.

METHODS

33 retrospective scoliotic cases instrumented with AVBT were used to computationally simulate their surgery and 2-year post-operative growth modulation using a finite element model. The cohort was divided into two subgroups according to the lumbar curvature evolution over 2 years: (1) correction > 10° (C); (2) maintaining ± 10° (M). The lumbar Cobb angle and residual ID wedging angle under LIV were measured. Simulated pressures and moments at the superior endplate of LIV + 1 were post-processed. These parameters were correlated at 2 years postoperatively.

FINDINGS

On average, the LIV + 1 simulated moment was 538 Nmm for subgroup C, 155 Nmm for subgroup M with lumbar Cobb angle > 20° and 34 Nmm for angle < 20° whereas the ID angle was 1° for C and 0° for M.

INTERPRETATION

On average, a positive moment on the LIV + 1 superior growth plate led to correction of the lumbar curvature, whereas a null moment kept it stable, and a parallel immediate postoperative ID under LIV contributed to its correction or preservation. Nevertheless, the significant interindividual variability suggested that other parameters are involved in the distal non-instrumented curvature evolution.

LEVEL OF EVIDENCE

IV.

Chiari 1: Is decompression always necessary previous to scoliosis surgery?

The association between Chiari 1 malformation and scoliosis is well known in the literature. Prevalence has increased after the advent of magnetic resonance imaging. In children with this association, prophylactic suboccipital decompression prior to scoliosis correction is a common surgical procedure although the rationale for this surgical management and whether not performing it may lead to spinal cord injury has not been clearly elucidated. We conducted a systematic review of the literature with the aim to obtain strong data to support the hypothesis that it is safe to proceed with scoliosis correction without prior prophylactic suboccipital decompression for Chiari 1 in an asymptomatic population. Using the Prisma methodology, we analyzed 3250 studies published between 1972 and 2018. Only four studies met the inclusion criteria. None of the studies had a level of evidence high enough to recommend prophylactic decompression previous to correction of the spinal deformity.

Feasibility of Single-Stage Posterior Passive Correction and Fusion Surgery for Congenital Scoliosis in Adolescent Patients Who Have Attained Skeletal Maturity

Study Design

Retrospective study.

Purpose

To report the perioperative and radiological outcomes of single-stage posterior passive correction and fusion (SSPPCF) in adolescent patients who present with congenital scoliosis.

Overview of Literature

The surgical treatment for congenital scoliosis is complex. There is no definitive guide on surgical options for skeletally matured adolescent patients who have congenital scoliosis.

Methods

Patients with congenital scoliosis who underwent SSPPCF using a pedicle screw system were reviewed. We identified the following three surgical indications: (1) hemivertebra or wedge vertebra over the thoracic or thoracolumbar region with structural lumbar curves, (2) hemivertebra or wedge vertebra at the lumbar region with significant pelvic obliquity or sacral slanting, and (3) mixed or complex congenital scoliosis. The demographic, perioperative, and radiographic data of these patients were collected.

Results

Thirty-four patients were reviewed. The mean patient age was 14.6±3.4 years. There were 13 hemivertebrae, three wedged vertebrae, two butterfly vertebrae, three hemivertebrae with butterfly vertebra, eight unsegmented bars, and five multiple complex lesions. The average surgical duration was 219.4±68.8 minutes. The average blood loss was 1,208.4±763.5 mL. Seven patients required allogeneic blood transfusion. The mean hospital stay duration was 6.1±2.5 days. The complication rate was 11.8% (4/34): one patient had severe blood loss, one had rod breakage, and two had distal adding-on. The Cobb angle reduced from 65.9°±17.4° to 36.3°±15.3° (p<0.001) with a correction rate (CR) of 44.8%±17.4%. The regional kyphotic angle decreased from 39.9°±20.5° to 27.5°±13.9° (p=0.001) with a CR of 19.3%±49.6%. Radiographic parameters (radiographic shoulder height, clavicle angle, T1 tilt, cervical axis, pelvic obliquity, coronal balance, and apical vertebral translation) showed significant improvement postoperatively.

Conclusions

SSPPCF was a feasible option for adolescent patients with congenital scoliosis who were skeletally matured.

Identifying risks factors in thoracolumbar anterior fusion surgery through predictive analytics in a nationally representative inpatient sample

PURPOSE

Anterior thoracolumbar (TL) surgical approaches provide more direct trajectories compared to posterior approaches. Proper patient selection is key in identifying populations that may benefit from anterior TL fusion. Here, we utilize predictive analytics to identify risk factors in anterior TL fusion in patients with trauma and deformity.

METHODS

In this retrospective cohort study of patients receiving anterior TL fusion (between and including T12/L1), population-based regression models were developed to identify risk factors using the National Readmission Database 2016-2017. Readmissions were analyzed at 30- and 90-day intervals. Risk factors included hypertension, obesity, malnutrition, smoking, alcohol use, long-term opioid use, and frailty. Multivariate regression models were developed to determine the influence of each risk factor on complication rates.

RESULTS

A total of 265 and 375 patients were identified for the scoliosis and burst fracture cohorts, respectively. In patients with scoliosis, alcohol use was found to increase the length of stay (LOS) (p = 0.00061) and all-payer inpatient cost following surgery (p = 0.014), and frailty was found to increase the inpatient LOS (p = 0.0045). In patients with burst fractures, malnutrition was found to increase the LOS (p < 0.0001) and all-payer cost (p < 0.0001), obesity was found to increase the all-payer cost (p = 0.012), and frailty was found to increase the all-payer cost (p = 0.031) and LOS (p < 0.0001).

DISCUSSION

Patient-specific risk factors in anterior TL fusion surgery significantly influence complication rates. An understanding of relevant risk factors before surgery may facilitate preoperative patient selection and postoperative patient triage and risk categorization.

Midterm surgical outcomes of a short fusion strategy for adolescent idiopathic scoliosis with Lenke 5C curve

BACKGROUND CONTEXT

A previous study examined the short-term (2 years) outcomes of a short fusion strategy for Lenke type 5C curves. This strategy had a little less correction rate with no difference in coronal and sagittal balance and SRS-22 scores to those of a conventional strategy and was superior in operative time and intraoperative bleeding. However, its effectiveness in longer follow-up periods was unknown.

PURPOSE

To assess midterm surgical outcomes of a short fusion strategy for adolescent idiopathic scoliosis (AIS) with Lenke type 5C curve, involving posterior correction and fusion surgery (PSF) using pedicle-screw constructs.

STUDY DESIGN

Retrospective case series.

PATIENT SAMPLE

Twenty-nine patients who underwent PSF for AIS with Lenke type 5C curve with a minimum 5-year follow-up.

OUTCOME MEASURES

Radiographic parameters and SRS-22.

METHODS

We compared radiographic parameters and clinical outcomes between patients with an upper instrumented vertebra (UIV) at the end vertebra (EV) (n=12) and those treated by short fusion (S), with a UIV one level caudal to the EV (n=17).

RESULTS

A preoperative mean Cobb angle of 51.9±13.8° was corrected to 11.7±7.7° in the EV group, and an angle of 46.0±6.6° was corrected to 9.3±5.2° in the S group. The correction was maintained in both groups at the final follow-up, and the mean correction loss was 2.8±6.8° in the EV and 6.5±6.5° in the S group (p=.143). The mean correction rate at the final follow-up was not significantly different between the EV (71.4±11.8%) and S (64.9±13.7%) groups (p=.199). A Cobb angle of a thoracic curve was significantly improved immediately after surgery and maintained during the follow-up period in the both groups. Coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, L4 tilt, UIV/LIV tilt, shoulder balance, and SRS-22 had no difference between the two groups.

CONCLUSIONS

There was no difference in radiographic parameters and SRS-22 between patients treated with a UIV at the UEV and patients treated using a short fusion strategy, in which the UIV was one level caudal to the UEV. The short fusion strategy can be one of the alternatives in PSF for Lenke type 5C curves, at least in 5-year time frame.

Stainless steel wear debris of a scoliotic growth guidance system has little local and systemic effect in an animal model

Options to treat early-onset scoliosis include guided-growth systems with sliding action between rods and pedicle screws. The wear was previously measured in an in vitro test, and in this in vivo rabbit model, we evaluated the local and systemic biological response to the stainless steel debris. Compared to the previous study, a relatively higher volume of representative wear particles with a median particle size of 0.84 μm were generated. Bolus dosages were injected into the epidural space at L4-L5 for a minimum of 36 rabbits across three treatment groups (negative control, 1.5 mg, and 4.0 mg) and two timepoints (12 and 24 weeks). Gross pathology evaluated distant organs and the injection site with a dorsal laminectomy to examine the epidural space and dosing site. Peri-implanted particle tissues were stained for immunohistochemical and quantitatively analyzed for IL-6 and TNF-α cytokines. Based on ISO 10993-6:2007 scoring, particles in the high-dose group were primarily non-irritant (12 weeks) with one slightly irritant. At 24 weeks, inflammatory cell infiltration was non-existent to minimal with all groups considered non-irritant at the injection site. Material characterization confirmed that particles detected in distant organs were stainless steel or contaminants. At 12 weeks, stainless steel groups demonstrated statistically increased amounts of cytokine levels compared to control but there was a statistical decrease for both at 24 weeks. These findings indicate that stainless steel wear debris, comparable to the expected usage from a simulated growth guidance system, had no discernible untoward biological effects locally and systemically in an animal model. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1980-1990, 2018.

Bone Morphogenetic Proteins in Pediatric Spinal Arthrodesis: A Statewide Analysis of Trends and Outcome of Utilization

INTRODUCTION

Bone morphogenetic protein (BMP) is considered off-label when used to augment spinal arthrodesis in children and adolescents. There is a paucity of longer-term information on BMP use in this population. The purpose of this study was to determine the rate of BMP utilization in pediatric spinal arthrodesis, assess factors associated with BMP use in this population, and evaluate long-term outcome.

METHODS

Spinal arthrodeses in patients 18 years and younger performed in New York State between 2004 and 2014 were identified through the Statewide Planning and Research Cooperative System database. All cases had a minimum 1-year follow-up. The primary outcome was revision arthrodesis. The primary outcome, as well as short-term and longer-term complications were identified using time-to-event analysis. Multivariable Cox proportional hazards models were used to assess the association between BMP and outcomes.

RESULTS

Of 7312 children and adolescents who underwent spinal arthrodesis, 462 (6.7%) received BMP. Utilization spiked between 2008 and 2010 when (8.6%) of cases received BMP, but subsequently BMP use returned to pre-2008 levels (2004 to 2007: 5.3%; 2011 to 2014: 5.5%). BMP was more likely to be used in children who were older (P=0.027), white and with higher mean family income (P<0.001 for race and income). BMP was more likely to be used for revision surgery, 2 to 3 level fusions, and spondylolisthesis (P<0.001 for all). Revision rates did not differ based on BMP utilization status. Patients receiving BMP did not have increased risk of short-term complications although at 5-year follow-up, BMP was associated with a statistically significant increased risk of mechanical complications (hazard ratio 1.48; 95% confidence interval, 1.02-2.14).

CONCLUSIONS

Off-label use of BMP for pediatric spinal arthrodesis increased until 2008 and now appears to be decreasing. Racial/ethnic minorities and lower socioeconomic status patients are less likely to receive BMP. The rate of revision after spinal arthrodesis does not differ between those treated with and without BMP. Further long-term studies are required to delineate appropriate guidelines for BMP utilization in children.

LEVEL OF EVIDENCE

Level III.

CT Radiation Dose Reduction in Robot-assisted Pediatric Spinal Surgery

STUDY DESIGN

Retrospective consecutive cohort series.

OBJECTIVE

The aim of this study was to develop a low-dose computed tomography (CT) protocol for use in robot-assisted pediatric spinal surgery.

SUMMARY OF BACKGROUND DATA

CT scans are utilized preoperatively for preoperative planning, by navigation software during robot-assisted surgery, and postoperatively to assess surgical implant placement. Traditionally high radiation doses produced by CT scanning are a concern in the highly radiosensitive pediatric population.

METHODS

We developed a low-dose protocol using phantom scans. A cohort of patients undergoing CT scanning using the low-dose protocol was collected. Further, a matching cohort of patients who underwent standard scanning was collected. Image quality was assessed by observer ratings. Radiation doses and image quality metrics were compared for the standard and low-dose protocol patients.

RESULTS

Effective dose significantly decreased 84% to 91% depending on patient size and whether the scan was preoperative or postoperative. All scans were compatible with the navigation software. No clinically significant differences in image quality were observed between low-dose and standard patient cohorts.

CONCLUSIONS

Task-based CT protocol optimization can produce acceptable image quality with dose comparable to standard two-view radiography.

LEVEL OF EVIDENCE

2.

Posterior correction and fusion surgery using pedicle-screw constructs for Lenke type 5C adolescent idiopathic scoliosis: a preliminary report

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To assess whether a short fusion strategy is applicable when treating adolescent idiopathic scoliosis with Lenke type 5C curve by posterior correction and fusion surgery using pedicle-screw constructs.

SUMMARY OF BACKGROUND DATA

Previous studies have discussed the selection of the lower instrumented vertebra to best preserve motion segments and obtain coronal balance. However, reports evaluating the selection of the upper instrumented vertebra when treating Lenke type 5C curves are not available.

METHODS

We evaluated 29 patients who were treated surgically for adolescent idiopathic scoliosis with Lenke type 5C curve (mean age, 16.8 ± 4.7 yr; range, 10-29 yr). The mean follow-up period was 28.0 ± 6.3 months (range, 24-48 mo). We compared radiographical parameters and clinical outcomes between patients with an upper instrumented vertebra at the end vertebra (EV) (n = 10) and those treated by short fusion (S group), with a upper instrumented vertebra 1-level caudal to the EV (n = 19 patients).

RESULTS

In the EV group, a preoperative mean Cobb angle of 50°± 15° was corrected to 8°± 7°, which was maintained at the final follow-up (7°± 1°). In the S group, a mean preoperative Cobb angle of 47°± 4° was corrected to 8°± 5°, but this increased significantly to 12°± 7° at final follow-up (P = 0.033). The mean correction rate at final follow-up was significantly lower in the S group (72%) than in the EV group (86%) (P = 0.027). Coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, L4 tilt, and clinical outcomes evaluated by Scoliosis Research Society patient questionnaire-22 were equivalent between the 2 groups.

CONCLUSION

Scoliosis Research Society patient questionnaire-22 scores and radiographical parameters other than the correction rate were equivalent between the 2 groups. A short fusion strategy, in which the upper instrumented vertebra is 1-level caudal to the upper EV, is applicable to posterior correction and fusion surgery with pedicle-screw constructs for Lenke type 5C curves.